tomorrow morning on "newsmakers," kentucky senator rand paul will talk about his support of mitt romney. he will also talk about his views on u.s. foreign aid. join us for "newsmakers" at 10:00 a.m. eastern on c-span. >> we want to introduce to you robert o'harrow, an investigative reporter at the washington post. he has been riding an occasional series on cyber security threats for that newspaper. mr. o'harrow, welcome to "the communicators." let's start with 0 day. what is zero day? >> zero day is the name that hackers give to a vulnerability and software that allows a bad guy into a computer system. these gaps take a lot of forms. they have not been previously discovered. so there is no way to block them. when a hacker has a zero day, with the right tools and school bills, they can't. into a system and take control. -- with the right tools and skills, they can take over system. >> how would you describe this series? >> it is really the mission that we were looking into cyber security and cyber war. the pentagon had declared cyberspace the environment of people and machines and networ